WASHINGTON - In some ways, the most striking thing about the shooting at the U.S. Holocaust Memorial Museum is the fact that the accused gunman is an octogenarian. The elderly are the least violent people in U.S. society, federal crime statistics show, being just a little more likely to commit homicide than preteens.

The FBI listed 17,040 homicides in 2007, the most recent year for which complete statistics are available. Of those, people 65 and older committed 156, or just under 1 percent. Teenagers ages 13 to 16 - just a four-year bracket - committed more than triple that number. The only age group that committed fewer homicides than the elderly were children 12 and younger.

James von Brunn, the 88-year-old man who allegedly shot and killed guard Stephen Johns on Wednesday at the Holocaust Museum, is the oldest homicide defendant in recent memory in the District of Columbia, according to the U.S. Attorney's Office. The agency does not keep records of defendants based on age, but a spokesman said an informal poll of prosecutors and detectives did not turn up any defendants past their 70s.

"No one has heard of someone this age," said Benjamin Friedman, special counsel for the agency.

Criminologists said the shooting was so unusual that it was not even an area of study. "I don't know of any study of older offenders," said Louis Schlesinger, professor of forensic psychology at the John Jay College of Criminal Justice in New York. "There would be no reason to target older people as offenders" because they are such a minuscule part of the criminal population, he said.

It does happen, of course. Frank Spillman, 94, was charged last year with killing his landlord in Oakland, Calif.

Lena Driskell was 79 in 2006 when she was charged with shooting her 85-year-old ex-boyfriend. Both were living in a senior citizens' high-rise in Atlanta when she discovered he was dating another woman.

But the FBI statistics bear out what psychologists and psychiatrists routinely say: Stereotypes about grumpy old men aside, men (and women, who commit about 10 percent of all homicides) become less violent for every year they live after age 25.

In men, surging testosterone levels, coupled with the relative immaturity of the brain's frontal lobes (the brain's executive center, which inhibits impulses), push homicidal violence to a peak between the ages of 17 to 24. Men in that age range were charged with 4,738 homicides in 2007. As in years past, this was by far the highest category.

For each five-year period thereafter, people committed fewer slayings, a steadily descending staircase of violence. By the senior years, a "wisdom of living" has settled in, said neuropsychiatrist Richard Restak, in which violence is rarely considered.

When impulse control is lost in later years, it is either very minor - think of the elderly complaining loudly about poor service or waiting in line - or is often a sign of deterioration in the frontal lobe, said Naftali Berrill, director of the New York Center for Neuropsychology and Forensic Behavioral Science, a private consulting firm that often works on mental evaluations in criminal cases.

"There's also an evolutionary reason why people become less violent in their later years," Berrill said. "Physical frailty makes it hard to engage in aggressive acts. You're more easily wounded. The elderly can't compete, physically, with the younger and stronger, so they don't."

Judge Postpones von Brunn Hearing

The white supremacist accused of killing a guard at the U.S. Holocaust Memorial Museum in Washington is too injured to appear in court, prosecutors said yesterday.

James von Brunn, 88,

is in critical but stable condition, U.S. Attorney Nicole Waid told a

federal judge.

Magistrate Judge John Facciola adjourned the case for a week to allow for von Brunn's condition to improve.

Von Brunn was shot in

the face after firing at security guard Stephen T. Johns, police said. Johns later died.

The judge appointed public defender A.J. Kramer to represent von Brunn. Kramer declined to provide details of his meeting with von Brunn or to say whether von Brunn was cooperating.

- Bloomberg News